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B. H. HALL.

v SCREW PROPBLLER. v No. 332,710. Patented Dec. 22, 1885.

Wi'fizeaes: J52 venior g &

N. PETERS. Phaloliflwgraphar, Washington, By C.

EDWVARD H. HALL, OF BROOKLYN, NEW YORK.

SCREW-PROPELLER.

SEECIPICATIQN forming part of Letters Patent No. 332,710, dated December22, 1885.

Application filed DecemherlS), 1884. Serial X0. 150,722.

To all whom it may concern.-

Be it known that I, EDWARD H. HALL, of the city ofBrooklyn, in thecounty of Kings and State of New York, and a citizen of the UnitedStates of America, have invented a new and useful Improvement inScrew-Propellers, of which the following is a specification, referencebeing had to the accompanying drawings,forming part of the same,in whichFigure 1 is a side view of a screw propeller containing my invention,and Fig. 2 is an end view of the same.

My invention consists in a screw-propeller, the blade of which iscomposed ofa body and two wings, and which extends entirely once aroundthe shaft on which it is mounted, and adapted and intended to be whollysubmerged, and having an elliptical opening in the body of the blade inthe portion thereof immediately adjacent to the shaft, said openingbeing concentric in curve to the shaft and the outer rim of theblade-body, and extending into the wings of the blade on each side toabout onethird the length of the wings from the axial line of the shaftto the edge or extremity of thewings,as hereinafter described andclaimed.

A is the shaft,and B is the propeller-screw, composed of the body andwings shown, and forming a continuous blade extending once entirelyround the shaftwith the appropriate pitch. The said screw is formed onor at taehed directly to the shaft. In the body of the blade is formedthe opening a, the said opening being elliptical in form or outline, andhaving a curve longitudinally, which is coincident to the circle orcurve of the shaft and that of the rim of the blade. The opening a isfurthermore located in that portion of the blade which is immediatelyadjacent to the shaft, but having a portion of the blade continuousaround and in contact with the shaft. The said opening a extends intoeach wing of the blade to about one-third of the (X0 model.)

length ofthe wing, measuring from the axial line of the shaft to the rimor extremity of the wing, as shown in Fig 2.

The screw propeller thus constructed is adapted and intended to bewholly submerged when it is operated as a propeller, and the fulladvantages of its peculiar construction are only obtained when it isthus submerged.

I am aware that screw-propellers have been heretofore constructed withopenings in their blades, and hence I do not claim such form andconstruction, broadly.

I intend to limit my claim hereunder to a screw-propeller composed of asingle blade extending entirely once around the shaft, and adapted andarranged to be operated when wholly submerged, having the opening a inthe body and wings of the blade, and located and formed as hereinparticularly set forth,

vwhereby in the operation of a blade of this specific description thedead-Water will be effectively cleared from the blade through the saidopening, and the lifting of such dcad-water and consequent loss ofpropellingpower be avoided.

\Vhat I claim as my invention, and desire to secure by Letters Patent,is

A screw-propeller adapted to be wholly submerged in operation,consisting ofan axial shaft, A,and a blade, B, extending helicallyentirely once around the said shaft, and having the elliptical opening ain that portion of the body of the blade which is immediately adjacentto the shaft, and extending, in a curve which is concentric to that ofthe shaft and the bladerii'n, into each wing of the blade about onethird ofthe distance from the axial line of the shaft to the extremityof the wing, as and for the purpose specified.

. EDWVARD H. HALL.

Witnesses:

A. G. N. VERMILYA, DAVID P. HERRICK.

